1. Field of the Invention
The present invention relates to a clutch actuator for a straddle-type vehicle and, more particular, to a clutch actuator mechanism to effect clutch engagement and disengagement with a smaller motor size.
2. Description of the Related Art
Clutch actuators often use a motor to cause a clutch mounted on a vehicle to move between an engaged state and a disengaged state. Normally, a biasing force acts to engage the clutch. In order to disengage the clutch, the motor must increase its output to overcome the biasing force. Some of such clutch actuators, such as that disclosed in Japanese Patent Publication No. 2000-501826, comprises elastic auxiliary means that enables reducing the power output required by the motor by canceling a portion of the biasing force with a counteracting elastic force generated by the elastic auxiliary means (see FIG. 2 of the Japanese patent publication).
With the related art, however, the force in the direction of clutch engagement and an elastic force of the elastic auxiliary means are caused to balance each other in the clutched state so that biasing the force in the direction of clutch engagement does not act on the clutch when the clutch is engaged. As a result, such prior clutch actuators can have insufficient stability with the clutch engaged.
A need therefore exists for an improved clutch actuator that has a reduced size and increased stability over prior actuator designs.